template <typename T1, typename... Ts>
void doSomething()
{
    ...
}

template <typename... Ts>
struct MyContainerCreator
{
    using type = boost::mpl::set<Ts...>;
};

using MyContainer= MyContainerCreator<T1, T2>;

void doSomethingForAll()
{
    //pseudocode:
    doSomething<expandTypesToTemplateParameters<MyContainer::type>>();
}

template <typename ... Ts>
void doSomethingForAll (MyContainer<Ts...> const & mc)
{
  doSomething<Ts...>();
}

template <typename>
struct foo;

template <typename ... Ts>
struct foo<MyContainer<Ts...>>
 {
   static void func ()
    { doSomething<Ts...>(); }
 };

template <typename MC>
void doSomethingForAll ()
 { foo<MC>::func(); }